S-114
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Does dual-chamber sensing
improve implantable cardioverter-defibrillator detection?
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Werner Jung, Christian Wolpert,
Susanne Spehl, Bahman Esmailzadeh*, Christian Schneider*, Thorsten Lewalter, Berndt
Lüderitz.
Departments of Medicine-Cardiology and *Cardiovascular Surgery, University of
Bonn, Bonn, Germany
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Abstract
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It has been reported that up to 25% of all patients
with implantable cardioverter-defibrillators (ICDs) receive unnecessary shocks due to
supraventricular tachycardia (SVT). Current ICDs use the tachycardia rate with or without
additional detection criteria such as rate stability and sudden onset or morphology based
ciriteria for arrhythmia discrimination. The introduction of atrial signal analysis may
allow for the reduction of inappropriate ICD therapy. We report on the long-term
experience with the first dual-chamber ICD (Defender 9001, ELA Medical, France) for
discrimination of ventricular tachycardia (VT) from SVT. This ICD device uses a new
arrhythmia detection algorithm based on the following criteria: rate, RR interval
stability, atrio-ventricular (AV) relation analysis and atrial or ventricular acceleration
in case of 1:1 AV relation.
Seventy patients were included in this study. During a mean follow-up of 9 ± 7
months, 330 spontaneous episodes were recorded by the internal memories and classified by
the device as VT (n = 160), ventricular fibrillation (VF, n = 22), or SVT (n = 148).
Stored data were reviewed by independent investigators who judged the classification
appropriate in all but 17 episodes. In 5 patients, 13 episodes of atrial fibrillation with
a rapid ventricular rate were treated inappropriately as VT. Three nonsustained VTs with
less than 10 seconds of duration and one sustained VT were classified as SVTs in 4
patients. Success rates were 86% for antitachycardia pacing and 100% for the first shock
therapy for the remaining episodes of VT and VF.
Conclusions. Dual-chamber ICDs provide equivalent efficacy and safety
rates compared to single-chamber ICDs. With the application of the new detection
algorithm, discrimination of ventricular tachycardia from supraventricular tachycardia is
achieved with a specificity of 92% and with a sensitivity of 99.3% for sustained
ventricular tachycardias. However, it is still unproven whether an additional atrial
sensing lead is really necessary to improve ICD specificity since new morphology based
criteria in a single chamber ventricular ICD may provide comparable sensitivity and
specificity rates.
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Key Words
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Implantable cardioverter defibrillator –
function, indications
dual chamber ICD, single chamber ICD, ICD inappropriate incidences, atrial signal
analysis, arrhythmia detection algorithm, discrimination ventricular/supraventricular
tachycardias, OA
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